Composite can with easy opening scored can opener end



g- 20, 1968 D. H. ELLERBROCK 3,397,809

COMPOSITE CAN WITH EASY OPENING SCORED CAN OPENER END 3 Sheets-Sheet 1Filed Aug. 26, 1966 K C O R mm E is M Ma w, H. D 4 M m F a H a FIG,5.

w I W Ilillll ATTORNEY 0, 1968 D. H. ELLERBROCK 3,397,809

COMPOSITE CAN WITH EASY OPENING SCORED CAN OPENER END Filed Aug. 26,1966 3 Sheets-Sheet 2 INVENTOR DONALD H. ELLERBROCK 62M MW ATTORNEY 0,1968 D. H. ELLERBROCK 3,397,809

COMPOSITE CAN WITH EASY OPENING SCORED CAN OPENER END 3 Sheets-Sheet 3Filed Aug. 26, 1966 I r. "'I

FIG.9.

INVENTOR DONALD H. ELLERBROCK ATTORNEY United States Patent 3,397,809COMPOSITE CAN WITH EASY OPENING SCORED CAN OPENER END Donald H.Ellerbrock, 1605 Gallant Fox Drive, Florissant, Mo. 63033 Filed Aug. 26,1966, Ser. No. 575,431 5 Claims. (Cl. 220-48) ABSTRACT OF THE DISCLOSUREThis disclosure relates to a metal end particularly designed for usewith a composite can to facilitate opening of the can with any of thevarious conventional can openers presently on the market and alsorelates to a composite can embodying such an end. The specificdisclosure relates to the positioning of a circumferential score linewhich will materially decrease the resistance to travel of the cutterelement of a can opener of the type having a toothed driving Wheel toprevent slippage of the driving wheel during the operation of the canopener,

Ever since the fibre-bodied composite can has been adopted as a low-costcontainer for certain products such as frozen juice concentrates andother products where the container is normally opened with aconventional can opener, it has been a constant problem for the fibrecan industry to develop a can which would permit easy opening with thevarious types of can openers presently in use. The paperboard materialusually used in fibre bodied composite cans is softer, more compressibleand thicker than the sheet metal material used in metal bodied cans.These different properties combine with the metal end conventionallyused on a fibre bodied can to produce a crimp or seam which is somewhatwider and more compressible than the seam of a metal bodied can.Conventional can openers were originally designed for use with metalbodied cans which inherently have a narrower stronger bead and also ahard metal wall to produce a positive supporting surface which preventspenetration into the body wall by the toothed driving wheel of the canopener and maintains said driving wheel in properly oriented drivingrelationship with the underside of the can bead, thus preventingundercutting and slippage of the driving wheel with respect to saidbead. With the softer fibre body of composite cans the driving wheelengages both the bead and adjacent outer body wall, and on certain canopeners tends to penetrate into the body wall causing the driving wheelto undercut the bottom edge of the bead.

In the United States a great number of inexpensive can openers are soldeach year. These cause most of the opening problems. Many of these canopeners are not sufliciently well made to work properly, even when new,and they do not stand up under the heavy usage given by the modern dayhousewife in this country. Even if these can openers dont work properlyon metal bodied cans the housewife continues to use them; and when usedon fibre bodied cans which provide less support than the metal bodiedcans, slippage problems occur sufiiciently often to be objectionable.Composite can opening problems have also occurred to a minor degree withcertain types of more expensive can openers due to the specificconstruction and arrangement of the driving and cutting parts of suchopeners so that the opening of a composite can with the can openerspresently in use has been a problem for fibre can manufacturers. Theapproach taken in United States Patent No. 3,201,259, assigned to theassignee of the present invention, materially improved the situation byproviding additional support for the can opener, but did not entirelysolve the problem.

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Employees of the assignee have continued to work on this problem andhave now provided a metal end particularly adapted for composite canswhich materially reduces the resistance of the cutter element to travelaround the metal end. It will be apparent that the drivmg force producedby the driving wheel against the can body and the underside of the beadmust always be greater than the resistance of the can opener to travelaround the can during the cutting operation. Thus, if this resistancecan be reduced, less driving force will be required and the possibilityof the toothed driving wheel slipping on the body and underside of thebead and thus losing its drive will be substantially reduced.

A number of factors influence the resistance to travel of the can openeraround the top of the can. One of these factors is the resistance tocutting or breaking through of the metal itself. Another is thefrictional resistance exerted by surfaces of the head on the elements ofthe can opener respectively engaged therewith. This materially increasesthe drag and resistance to movement of the can opener around the canwhich in turn causes slippage of the driving wheel, since the totalresistance to travel becomes greater than the driving force produced bythe driving wheel of the can opener. If the total resistance to travel(the resistance to cutting or breaking through the metal plus the dragresistance exerted by the can opener elements riding on the engagedsurfaces of the bead) is less than the driving force produced by thedriving wheel the can will be easily opened by the can opener.

There is a substantial difference in the average diameter of the cutterpaths of the various can openers. This can be readily determined bymeasuring the diameter of the cut out discs produced by the variousdifferent can openers after opening an unscored metal end. This can beaccomplished by taking a number of circumferentially spaced readingsacross the diameter of said cut out disc and averaging these readings todetermine a definite average diameter thereof. The positioning of thepreweakening circumferential score line substantially ad- -jacent thecircumferential path of the cutter element of the can opener materiallyimproves the opening characteristics of the metal end closure of thefibre bodied composite can. However, because of these variations in thediameters of the circumferential paths of the cutter elements of thevarious can openers it is impossible to provide a single score diameterwhich would substantially coincide with the cutter path of all canopeners. Through extensive experimentation with various score diametersI have discovered that the best and most reliable openingcharacteristics with respect to all different types of can openers areobtained when the diameter of the score line is at least as great as orgreater than the average diameter of the cut out disc produced by theparticular can opener construction which cuts the largest size disc. Inother words, the tests which have been run definitely indicate thatpositioning the score line outboard of the path of the can opener cutteris necessary to reduce the force required for the cutter element tobreak through and cut out the central closure disc of the metal end.

For purposes of this application outboard means radially outwardly awayfrom the center of the metal end or outwardly toward the bead or chimeof the can seam and inboard means radially inwardly toward the center ofthe metal end.

It is therefore an object to provide a composite can structure having alaminated hollow body with at least one layer of fibrous paperboardmaterial and end closures on the ends of said body, at least one of saidend closures being an easy opening metal end provided with acircumferential score line lying substantially adjacent the cir- 3cumferentially path of the cutter element of a conventional can opener.

It is another object of the present invention to provide an easy openingscored can opener end for a composite can of the type described, whichend is specifically pre-weakened by a circumferential score line lyingsubstantially adjacent the circumferential path of the cutter element ofa conventional can opener of the type having a toothed rotary,bead-engaging driving wheel and a cutter element for circumferentiallycutting out the metal closure panel of said easy opening end, saidcircumferential score line reducing the force required to break and cutthrough said metal end and thereby reduce the driving force required todrive said cutter element around said metal end to cut out the closurepanel of said end and thereby facilitate opening the can.

It is a further object to provide a metal end having a circumferentialscore line the diameter of which is at least as large as or larger thanthe average diameter of the circumferential path of the cutter elementof a conventional can opener of the type described.

These and other objects and advantages will more fully appear from thefollowing description made in connection with the accompanying drawingswherein like reference characters refer to the same or similar partsthroughout the several views, and in which:'

FIG. 1 is a front elevational view of a composite container,

FIG. 2 is an enlarged fragmentary vertical sectional view showing atypical composite can wall construction,

FIG. 3 is an enlarged fragmentary vertical sectional view showing thescored end,

FIG. 4 shows a can opener as it is initially applied to a canimmediately before the cutter element is projected downwardly toinitially puncture the metal end of the can,

FIG. 5 is a view similar to FIG. 4 showing the cutter element inoperative cutting position after the same has been forcibly projectedthrough the can end,

FIG. 6 is a top perspective view showing a can opener in operativeposition on a typical can,

FIG. 7 is a front perspective view thereof showing the can opener beforebeing clamped into operative position by dotted lines and in operativeposition by full lines,

FIG. 8 is a sectional view of a can showing from the inside a can openerin operative position thereon, and FIG. 9 is an enlarged fragmentaryperspective view of the can end with the can opener shown in cuttingposition.

One form of a composite can body has been shown for purposes ofillustration in this application. The composite can body illustratedherein has a spirally wound laminated body wall 10 with a pair of metalend closures 11 and 12 attached thereto as shown in FIG. 1. This bodywall 10 has a spirally wound inner body ply 13 which in the form shownhas a skived, overlapped and adhesively connected spiral joint 13a. Asuitable outer wrapper or label 14 is adhesively connected to the outersurface of the body ply 13 and a liner 15 is adhesively connected to theinner surface of the body 13. In the form shown the inner liner has afold-over lap joint 15a which is provided to improve the barrierproperties of the liner where a barrier is required. Obviously, morethan one ply of body stock material could be used depending upon therequired strength of the body wall and the body wall could take the formof a convolute or lap seam construction, both of which have been used bythe fiber can industry.

At least one of the metal ends such as the upper end 11 is provided witha pre-weakened circumferential area such as is produced by the scoreline formed in the outside surface of the end. This score line 20extends around the outer circumference of the central depressed closurepanel of the end 11 and lies in the upper portion of the circumferentialradius which connects said central panel with the upstanding wallportion 21 against which the outer bead portion 22 is pressed andsupported. The diameter of this score line 20 is at least as large as orlarger than the diameter of the cut out disc produced by the can openerwhich produces the largest sized disc. This positions the score 20substantially adjacent the circumferential path of the cutting edge 25aof the cutter element 25 of the can opener which normally produces thelargest diameter cut out. The metal used in the scored end 11 must besufficiently hard to prevent tearing away thereof by the toothed drivingwheel. The steel conventionally used for metal ends is satisfactory;however, conventional metal end aluminum is too soft.

The most popular type of can opener in use today is the scissor or pliertype, such as the can opener shown in FIGS. 4 through 9. This can openerhas a pair of levers 26 and 27. A mounting plate 28 fixed to the lever27 is pivotally connected to the lever 26 as by a rivet 29. The upperportion of the plate 28 has the cutter element 25 formed thereon. Atoothed driving wheel 30 is journaled at the end portion of the lever 26on the opposite end of the pivot 29 from the gripping handle 26a and aturning handle 31 is provided for rotating the driving wheel 30. As bestshown in FIG. 5 and by the full line position in FIG. 7 the can openeris applied to the seam. The levers 26 and 27 are squeezed together toproject the cutting edge 25a of the cutter element 25 into cuttingposition and the driving wheel 30 in engagement with the underside 26aof the seam 22 as well as with the portion of the body wall adjacentthereto. It is important that the bead 22 have sufiicient strength toresist collapsing under the pressure produced by the cutter 25 and thedriving wheel 30. After initial piercing operation the turning handle 31is rotated to drive the cutter wheel and cause the cutter element totravel around the inside of the body wall to cut out the panel of themetal end and open the end of the can. The driving force produced by thedriving wheel 30 in engagement with the lower edge 22a of the head 22must be greater than the resistance produced by the cutter edge 25acutting through the metal end and the frictional resistance to travel ofthe can opener around the circumference of the can. By providing theweakened score line the resistance to cutting is substantially reducedand thus the driving force produced by the driving wheel 30 ismaintained at a higher level than the drag produced by the openingoperation.

By maintaining the score line 20 outboard of the outermost cutterelement of all the can openers in use, the weakening produced by thescore line is effective in reducing the force required to cut throughthe metal. However, when the score line is inboard of the path of thecutter element, the cutter element will generally cut through the metaloutboard of the score line so that a score line inboard of the cutterelement is completely ineffective in reducing the resistance to breakthrough essential to solving the can opening problem.

Difierent can diameters and body wall constructions produce differentbody wall and seam thicknesses. In general, the larger the can diameterthe thicker the body wall. Also in general, the thicker the body wallthe greater the frictional resistance of the can opener to travel aroundthe can. The thickness of the body wall, the profile of the seam of themetal end an the configuration of the metal end will all producevariations in the diameter of the circumferential path of the cutterelement of the can opener. Therefore, the specific design of the scorediameter and score depth may vary with each can size and construction.

For example, in the case of the 202 x 314 container presently being madefor the citrus concentrate industry, the inside diameter (in inches) ofthe can body wall is 2.0625 and the diameter of the score line 20 is2.035. I have found that this score diameter is larger than the averagediameter of the circumferential cutter path produced by the various canopeners tested. In the case of the 211 X 414 containers also producedfor the citrus concentrate industry, the inside diameter (in inches) ofthe can body wall is 2.573 and the diameter of the score line which islarger than the largest diameter of the circumferential cutter pathproduced by the various can openers is 2.550.

It is, of course, obvious that there is sufficient residual metal leftat the score line to provide sufiicient strength to hold the productconfined within the can under usual shipping and handling conditions andthis is also critical in connection with the specific can designs forthe various products to be packaged.

Since the problem of slippage of the can opener driving wheel 30 hasbecome particularly critical with the increased use of paper bodiedcomposite cans, this is the problem which has been solved by thisinvention and the scope of this invention will be limited to compositecans having a fibrous layer of material incorporated in the laminatedbody wall thereof.

It will be seen that I have provided a relatively simple and economicalyet highly eflicient solution to the problem which, in spite of the factthat more than one billion composite cans have been sold by the fibrecan industry since they were first introduced by applicants assignee in1960, and in spite of the fact that this problem has existed with all ofthese cans, the present invention constitutes the first successfulsolution to the cornposite can, can opening problem. In the past, scoredaluminum tear-out ends which require the use of a starter tab and aredesigned to eliminate the use of a can opener entirely have been triedbut have not been generally accepted by the trade since certain problemshave occurred with their use, and also since they are considerably moreexpensive than the standard can opener type end. Applicants inventionprovides a metal end which not only solves the problem but which can beproduced at a cost only slightly greater than the cost of a standardmetal end. While the score in the outside surface has been found to bemore easily formed in production, this score would serve the samepurpose if formed in the inside surface of the metal and.

It will, of course, be understood that various changes may be made inthe form, detail, arrangement and proportion of the parts withoutdeparting from the scope of my invention which generally stated consistsin the matter set forth in the appended claims.

What I claim is:

1. A composite can comprising a hollow laminated body including at leastone layer of fibrous paper material and having a pair of end closuresrespectively closing the ends of said body, one of said closuresconstituting a metal end seamed onto one end of said body andspecifically designed to facilitate opening thereof with a can opener ofthe type having a cutter element and a toothed driving wheel, said metalend having a circumferential score line formed therein defining acircumferential cutting line lying in the approximate path of the cutterelement of the can opener to reduce the resistance to travel of the canopener around the can.

2. The structure set forth in claim 1 and said circum ferential scoreline lying in the connecting radius between the central closure panel ofsaid metal end and the circumferential upstanding inner wall of theseam.

3. The structure set forth in claim 1 and the diameter of saidcircumferential score line being at least as great as the diameter ofthe largest circumferential path produced by the cutter element of anyconventional can opener during its travel around the outside of thecentral closure panel.

4. A metal end for closing at least one end of a composite can of thetype having a hollow laminated body including at least one layer offibrous paper material, said metal end being specifically constructed tofacilitate opening thereof with a can opener of the type designed totravel around the head of the metal end and having a cutter element tocircumferentially cut out the central closure panel of the end andhaving a toothed driving wheel for producing the desired circumferentialtravel around the head, said metal end being characterized by having acircumferential score line positioned to reduce the resistance tobreakthrough of the metal end by the cutter element at the score line topermit the driving wheel of the can opener to drive, without slipping,the cutter element around the outer circumference of the central closurepanel and said circumferential score line lying in the connecting radiusbetween the central closure panel of the metal end and thecircumferential upstanding inner wall of the seam.

5. A metal end for closing at least one end of composite can of the typehaving a hollow laminated body including at least one layer of fibrouspaper material, said metal end being specifically constructed tofacilitate opening thereof with a can opener of the type designed totravel around the head of the metal end and having a cutter element tocircumferentially cut out the central closure panel of the end andhaving a toothed driving wheel for producing the desired circumferentialtravel around the head, said metal end being characterized by having acircumferential score line positioned to reduce the resistance tobreakthrough of the metal end by the cutter element at the score line topermit the driving wheel of the can opener to drive, without slipping,the cutter element around the outer circumference of the central closurepanel, and the diameter of said circumferential score line being atleast as great as the diameter of the largest circumferential pathproduced by the cutter element of any conventional can opener during itstravel around the outside of the central closure panel.

References Cited UNITED STATES PATENTS 1/ 1963 Henchert 22067 7/1965Saunders 229-55

